Electric discharge tube



July 19, 1932. G. SEIBT ELECTRIC DISCHARGE TUBE.

Original Filed Sept. 25, 1924 R f 3% M6 1.5 m 0. e "la Patented July 19, 1932 UNITED STATES PATENT OFFICE GEORG SEIBT, OF

IBERLINT-SCHONEBERG, GER-MANY, ASSIGNOB TO RADIO CORPORA- TION OF AMERICA, A CORPORATION OF DELAWARE ELECTRIC DISCHARGE TUBE Original application filed August 26, 1921, Serial No. 495,504, Patent 24, 1913. Divided and this application filed September 25,

No. 1,592,387, and in Germany October 1924, Serial No. 739,882. Patent No.

1,696,103. Again divided and this application filed December 11, 1928, Serial No. 325,307.

(GRANTED UNDER THE rnovrsrons or THE new or lumen a, 1921, 41 arm. 1., 1313 amplifying, or generating alternating currents, the said tubes being of the kind comprising a heated filament acting as a cathode which emits electrons, an anode to which a positive potential is imparted by its being connected to the positive pole of a local source of direct current and on which the electrons emitted by the cathode impinge, and a controlling electrode or grid to which the currents to be controlled are applied and which under the influence of the latter currents varies the flow of the electrons from the cathode to the anode.

According to the invention forming the subject matter of the present application, which is a division of my application Serial No. 739,882, filed Sept. 25, 1924, patented on December 18, 1928, as United States Patent 1,696,103, itself a division of my application Serial No. 495,504 filed Aug. 26, 1921, patented on July 13, 1926, as United States Patent 1,592,387, connections are supplied for securing detection, amplification or generation of alternating current in a four electrode discharge tube of the kind referred to in the parent applications in which a heated cathode is associated with a grid, a second grid and an anode.

It is to be understood that throughout this specification, the word grid is intended to cover a controlling electrode to which the currents to be controlled are applied and which allows a stream of electrons to pass through it, and the term anode to cover an electrode which is always connected to the positive pole of a local source of direct current so as to receive a positive potential.

I have illustrated in the figure the type of electric tube and the connections necessary for carrying out the object of my invention.

Between the filament F and the outer metallic cylindrical tube III, which acts as anode, are arranged two concentric grids I and II insulated from one another. To one of the two grids, the grid I, for example; is applied an auxiliary potential. The potential is produced by the battery B and may be varied by means of a contact sliding on a resistance P. The auxiliary potential ma also be applied to the grid II in lieu of the grid I. It is also possible to apply the auxihary potential to both grids. In the example shown the alternating current to be detected or amplified is applied to the grid II. The high frequency current passing a coil W is induced in the oscillating circuit S connected to the grid II. A is the battery for heating the filament F, H the anode btattery, T the telephone and J a galvanome er.

The object of the auxiliary potential applied to one of the grids is to increase the sensitiveness of the arrangement. It is ob- VlOllS that the stream of electrons can by this means be so affected that it regulates the formation of the stream of electrons between cathode and anode. In other words, this potential establishes an electrical field which serves the purpose of either accelerating or retarding the stream of electrons emerging from the cathode and in this way make it moge susceptible to the action of the second gri The illustration shows the two grids surrounding the filament and the plate surrounding the two grids. Such an arrangement wherein all of the electrons have to pass through the two grids before reaching the plate possesses the advantage that the full stream of electrons is subjected to control and that, therefore, the action of the two controlling elements is more sensitive and elfective.

While the preferred embodiment of the present invention has been specifically illustrated and described, it is to be understood that the present invention is not limited to its illustrated embodiment but may be embodied in other connections of electric discharge tubes within the scope of the invention, as particularly pointed out in the following claims.

I claim:

1. A high frequency circuit, comprising a vacuum tube with a cathode, a surrounding anode, and at least two control electrodes connected-to the "an concentric with and surrounding said cathode and input circuit, connected to one of said control electrodes, an output circuit connected to said anode, and means for im- 8 presing on one of said control electrodes a constant positive potential with reference to the other control electrode.

2. An apparatus for converting alternating current, comprising a vacuum tube with a cathode, a surrounding anode and a plurality of control electrodes surrounding said cathode, a source of auxiliary otential connected to maintain a substantially constant difierence or potential between said control electrodes, an input circuit connected to one of said control electrodes to impress upon it an alternating potential, and an output circuit connected to said anode.

3. An electron valve circuit, comprising a vacuum tube with a cathode, a surrounding anode and at least two control electrodes surroun stant auxiha potential applied to one of said control e ectrodes, an input circuit conas nected to another of said control electrodes,

and an output circuit including a supply of direct current to establish the electronic flow connected to said anode. 1

4. Apparatus for converting alternating cathode, a control electrode surrounding said cathode, an adjustable auxiliar source of voltage applied to said electr control electrode surrounding the cathode and the firstcontrol electrode, an input cir cuit connectedto' said second control elec'- trode, an anode surroundin the cathode and both of said control electr es, and an output circu} clplmlilecftreedltosaid anode. p 5. uen circuit com a vacuum t be with a athode, a control diec trode surrounding said cathode, an adjustable auxiliary'source of voltage applied to said electrode, a second control electriide surli rounding the cathode and the first control electrode, all of said electrodes being concen tricall 'an input circuit connected to sai second control electrode, an anode surrounding the cathodeand both of said control electrodes, and an output circuit 0on 'necteg to slaidfrgiode;

6. Y uency circuit comprising an electron lfischarge device inclu od an anode, a plurality of control electr es, means for impressing high frequency currents upon one of the control electrodes and connected to the cathode and said latter said cathode, a source of concurrent, comprising a vacuum tube with a I e, a second messesnected to said anode, an in ut circuit connected to one of said contro electrodes, and

means for maintaining said other control potential with referan input circuit connected to one of said con-v trol electrodes, and means for maintaining said other control electrode at a positive po tential with' reference to said cathode.

In testimony whereof, I have hereunto subscribed my name this 28th day of November,

GEORG' SEIBT.

a cathelectrode, means for biasing another one of the control electr and an out at circuit e and cath e. 7. The'ombination with an electron dis- I charge device having an electron emitting "cathode, two control electrodes said cathode, and an-anode surrounding said control electrodes, of an output circuit con 

